ИСТИНА

The ice core records in mid-latitudes drilled in Europe have been limited by melt processes, with the only one millennium climate record from a non-temperate glacier obtained in European Alps. In August 2020, a 96.1 m ice core was drilled to bedrock at Elbrus Eastern Summit in the Caucasus (42°20’50’’N, 42°27’15’’E, 5600 m a.s.l.), representing the highest possible location for ice core drilling in the European continent. The drill site situated in the center of a volcanic crater with a maximum depth of 100 m based on GPR surveys. The borehole temperature at a depth of 15 m was -15°C, and the firn/ice transition occurred at 18 m depth. The ice core was analyzed using continuous flow analysis (CFA) at the British Antarctic Survey for d18O, dD, d-excess, dust, NH4, NO3, SO4, and CH4, with supplementary SEM scans of 120 discrete samples. Additional discrete ion chromatography and trace element analysis were completed in IGRAN ice core Lab. Dating was performed using radiometric dating (210Pb, 3H), and 3-D ice flow modeling. The age estimate at 10 m w.e. depth was 1820 CE (± 20 years), with 210Pb and 3H agreeing within 2 years. The glacier's velocity field in the crater of Mount Elbrus Eastern Summit was calculated using a three-dimensional steady-state thermomechanical full Stokes model. Elmer/Ice was utilized for the calculations, indicating the ice's age at a depth of 75 meters to be between 882 and 1176 years. This study presents a high-resolution millennium environmental record, including changes in d18O, dust, NH4, NO3, SO4, and methane for the first time in the European Continent. The record reveals a significant anthropogenically-induced rise in aerosol and methane concentrations. Sulfate, nitrate, and ammonium exhibit an onset of a three-fold 1950 AD rise. The 1000-year record was used to investigate the natural variability in isotopic composition resulting from temperature and NAO changes. The dust record provides insights into temperature and precipitation changes in dust source regions located in Northern Africa and the Middle East. The lowest 20 m of the ice core potentially offers the longest ice core record for the region.